Large open chronic wounds typically secrete exudates during the healing process. It is generally desirable to remove these wound exudates from the wound vicinity to minimize bacterial growth which can cause infection and delay healing. Excessive exposure to wound exudates can result in maceration of the skin surrounding the wound. Wound exudates are known to contain tissue degrading enzymes that can impede wound healing. It is generally known to cope with exudates of large open chronic wounds by packing them with an absorbent packing such as gauze. Gauze packing fills dead space in the wound and absorbs exudates released by the tissue over time. Disadvantageously, the absorbent gauze must be replaced periodically as it absorbs a larger volume of exudates and becomes saturated.
Alternatively, removal of wound exudates can be accomplished with suction. The wound is sealed generally by the application of a cover and suction is applied to the wound to draw out exudates. Often the suction is applied continuously for days or weeks. When suction is used it can be beneficial to also use wound packing. The wound packing provides passages from the areas where it contacts the wound to communicate the exudates from the wound surface towards the source of suction. When wound packing is used in conjunction with suction it is generally found that wounds heal more quickly and wound packing may be replaced less frequently because exudates are continuously removed.
When absorbent wound packings such as gauze are used with suction their highly absorbent characteristics are not required. Cotton gauze typically absorbs from ten to twenty five times its weight in aqueous liquid. This absorbent quality can be detrimental because absorbent packings tend to retain volumes of exudates within the wound cavity and adjacent the wound surface supporting bacterial growth and enzymatic breakdown of tissue.
When suction has been applied to the wound, it is generally desirable to permit the wound to contract. Wound contraction is a normal part of wound healing, therefore using a packing that encourages contraction, as opposed to inhibiting it, is desirable. When a noncompressible wound packing, such as gauze, is used in conjunction with suction, the wound contraction may be impeded by the wound packing.
An alternative to gauze as a wound packing is foam. Foams have the disadvantage that they are not readily modified by many traditional methods, such as heat stamping, to produce a surface texture after they are formed. Foam formation methods do not readily lend themselves to the construction of composites. This limits the extent to which multiple materials can be integrated into the foam structure during the manufacturing process. Foam materials are isotropic in that they exhibit uniform properties such as absorbency, pore size etc. in all directions. When used with suction foams, have the disadvantage that pieces can easily be separated from the whole, when removed from the wound. This is caused by new tissue growing into the foam structure. This can be problematic because often it may not be possible to see the pieces of foam that remain in the wound.
Hence, known wound packing materials have a number of disadvantages and as such there is a need for a superior wound packing.